Date: Wed, 22 May 1996 20:48:35 -0400
From: der Mouse <mouse@Collatz.McRCIM.McGill.EDU>
After exchanging some email with Theo (Theo! gasp! :-) on the subject
of this can of worms about reserving part of a swap area to avoid
swapping over disk labels and the like, the alternative that seems best
to me is to define a new ioctl for disk drivers. If we call this
ioctl, for the sake of argument, DIOCSWAPSKIP, then the idea is that
the swap code does a DIOCSWAPSKIP on the swap device to find out how
much it should skip.
What SunOS does is when it is told to start swapping on a partition,
it checks out what the absolute "entire disk" starting block is for
the slice, and if it is zero or less than the space occupied by a
disklabel etc. then it adjusts the base block to the "safe" starting
block.
Later,
David S. Miller
davem@caip.rutgers.edu